1. Field of Invention
The present invention relates to a sacroiliac belt having a lengthwise non-elastic inner belt for snugly encircling the user's hips and a lengthwise elastic outer belt secured between the back and sides of the inner belt to establish elastic compression on the sacroiliac joint. The invention also relates to a lengthwise non-elastic foam-fabric composite structure for use in sacroiliac belts and other non-elastic orthopedic braces and supports for wrapping around a part of the body.
2. Background Art
A sacroiliac belt is worn around the upper hips, to exert a compressive force around the pelvic girdle, and stabilize and reduce strain in the sacroiliac joint. The technical literature provides details on the placement of sacroiliac belts, and medical, physiological, anatomical and other considerations concerning sacroiliac belts. Therefore, although these considerations are discussed briefly as background information concerning the invention, it will be understood that the practitioner will have or readily obtain a more complete understanding of such aspects and considerations concerning sacroiliac belts from the literature.
One type of sacroiliac belt disclosed in the art includes an elastic inner part that wraps around the user's hips and a non-elastic outer part that encircles the inner part to establish an overall non-elastic sacroiliac belt. Brunswick, U.S. Pat. No. 4,572,167 discloses a sacroiliac belt of this type, with elastic panels and a non-elastic cinch strap encircling the panels. Another sacroiliac belt of this type includes elastic Neoprene to wrap around the user's hips and non-elastic Nylon to wrap around the Neoprene. This sacroiliac belt is not recommended for wearing directly against the skin because the closed-cell structure of Neoprene causes heat build-up which can lead to skin irritation. The overall non-elastic nature of such sacroiliac belts is also not preferred by many practitioners because the outer encircling part typically includes a cinchable fastener arrangement, such as a buckle or cinch, that allows a person additional leverage so that it is possible to pull the sacroiliac belt tighter than it should be. As a result, the overall non-elastic sacroiliac belt of this type can reduce available motion in the sacroiliac joint below its normal range of motion. With reduced motion, the inflow of nutrients and oxygen is reduced and the outflow of cellular waste products is reduced. These waste products are acidic, which lowers the pH within the joint. The body then shunts in calcium to neutralize the acid and arthrosis can develop. Buckles and other fastener arrangements used in such belts can also pinch and be otherwise inconvenient or irritating to the user.
Variations on the overall non-elastic sacroiliac belt with an encircling outer belt are also known in the art. For example, Hyman et al., U.S. Pat. No. 4,576,154 discloses a sacroiliac belt with an inner non-elastic woven belt and small cinch straps securable between the ends of the inner belt. Tyo, U.S. Pat. No. 4,696,291 provides a sacroiliac belt with string lacing to secure rigid plastic support members in position. Sacroiliac belts of this type can also be overtightened by the user, and providing optimum support for pelvic girdle considerations that vary from one individual to another in belts using non-flexible elements (such as in Tyo) presents additional difficulties.
Another type of prior sacroiliac belt is generally elastic, which allows good compression of the sacroiliac joint. The elastic sacroiliac belt will not typically compress too much, to the point of limiting motion of the sacroiliac joint below normal. However, an overall elastic sacroiliac belt gives a false sense of security to the user because the actions that open the sacroiliac joint, i.e., bending, lifting, and twisting, can force the joint open beyond its normal range of motion even with the sacroiliac belt in place. In other words, sacroiliac elastic belts do not create a stop point at the end of the normal range of motion of the sacroiliac joint. As ligaments are essentially non-elastic, movement of the sacroiliac joint beyond its normal range will stress the ligaments and potentially re-injure the joint.
Another sacroiliac belt includes an inner belt of non-elastic woven cotton and an outer elastic belt. The inner belt is secured around the user's hips with a hook and loop fastener or other non-cinchable fastener to establish a non-elastic belt that mimics the function of the sacroiliac ligaments in the sense that non-elastic belt allows the sacroiliac joint to open to the end of its normal range of motion and stop further opening of the joint. The outer belt is elastically secured between the back and sides of the inner belt, partially encircling inner belt, to provide the user with a sense of elasticity within the normal range of motion of the sacroiliac joint. Hand tightening this sacroiliac belt creates sufficient tension to compress the soft tissues so that the sacroiliac belt can create the correct stop point at the normal end of range of sacroiliac joint motion, but this sacroiliac belt cannot be tightened too much as to restrict sacroiliac joint motion below its normal range of motion.
A problem with all prior sacroiliac belts is that there is no convenient or comfortable way to attach it to conventional clothing, and due to the inward curvature of the upper part of the hips, the sacroiliac belt can slide up as the user moves around. It is possible to mechanically secure the sacroiliac belt, such as looping a cord or other material from the sacroiliac belt, under the hips, between the legs, and then back up to the sacroiliac belt on the other side of the body; but such arrangements are uncomfortable and inconvenient for the user. Some sacroiliac belts use side patches of open-weave material with rubberized or soft polyvinyl chloride (PVC) composition coating (such as sold under the trademark “GRIPTEX”) on the inside of the belt for the suggested purpose of assisting in holding the belt in position. Such patches rely on development of a tackiness or rubber-type surface friction component for gripping purposes with the belt snug around the user. However, in practice, such patches do not exhibit sufficient gripping to hold the sacroiliac belt in position under many conditions or over many materials of clothing. Coating of the weave material results in a relatively smooth surface characteristic which, although somewhat tacky when dry, becomes slippery when wet. Consequently, such patches contribute very little gripping when the belt is worn directly against the skin due to likely presence of small amounts of sweat. The composition of the coating can also be irritating to some people if the sacroiliac belt is worn against the skin.
Thus, there is a need for a sacroiliac belt that addresses the above-identified disadvantages and drawbacks of prior sacroiliac belts. In particular, there is a need for a sacroiliac belt that provides controlled support with limited elasticity within the normal range of motion of the sacroiliac joint, but that can be worn directly against the skin without causing irritation to the user and that remains in place while the user moves around regardless of whether worn against the skin or over clothing.